Gap (compression-only) link objects may be used to model vertical deflection, including that of beams on an elastic foundation. Gap links may be applied as follows:
Set stiffness and open distance through Nonlinear > Modify/Show.
Figure 1 - Set stiffness and open distance
Please note that both links and springs are available for modeling, though links are more powerful because they enable nonlinear behavior and may be used either as supports or as connections between two non-grounded joints. Nonlinear link properties are only active when running a nonlinear load case.